Aerosol-generating system and aerosol-generating article comprising an aerosol-forming substrate

ABSTRACT

An aerosol-generating system is provided, including an aerosol-generating article and an aerosol-generating device, the article having an upstream end and a downstream end, and defines a longitudinal direction and includes an upstream segment and a downstream segment, the upstream segment includes an aerosol-forming substrate having a substrate outer surface with a substrate outer diameter, the downstream segment having a downstream segment outer diameter greater than the substrate outer diameter, the device including a device cavity inner surface having a device cavity inner diameter, the device cavity being configured to receive at least the aerosol-forming substrate, the device further including at least one heating element, and when the aerosol-forming substrate is received in the device cavity, an airflow passage is defined between the substrate outer surface and the device cavity inner surface.

The invention relates to aerosol-generating articles, aerosol-generating devices and aerosol-generating systems comprising aerosol-generating articles and aerosol-generating devices.

Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco containing substrate, is heated rather than combusted are known in the art. An aim of such heated aerosol-generating articles is to reduce harmful or potentially harmful by-products produced by the combustion and pyrolytic degradation of tobacco in conventional cigarettes.

In aerosol-generating articles, an inhalable aerosol is typically generated by the transfer of heat from a heating element to an aerosol-forming substrate. During heating, volatile compounds are released from the aerosol-forming substrate and become entrained in air. For example, the volatile compounds may become entrained in air drawn through, over, around or otherwise within the vicinity of the aerosol-generating article. As the released volatile compounds cool, they condense to form an aerosol. The aerosol may be inhaled by a user. The aerosol may contain aromas, flavours, nicotine and other desired elements.

The heating element may be comprised in an aerosol-generating device. The combination of an aerosol-generating article and an aerosol-generating device may form an aerosol-generating system.

In an aspect of the invention, an aerosol-generating system is provided, the system comprising:

-   an aerosol-generating article having an upstream end and a     downstream end, the aerosol-generating article defining a     longitudinal direction between the upstream end and the downstream     end, the aerosol-generating article comprising:     -   an upstream segment disposed at the upstream end of the         aerosol-generating article, the upstream segment comprising an         aerosol-forming substrate, the aerosol-forming substrate         comprising a substrate outer surface having a substrate outer         diameter; and     -   a downstream segment disposed at the downstream end of the         aerosol-generating article, the downstream segment having a         downstream segment outer diameter, the downstream segment outer         diameter being greater than the substrate outer diameter; and

an aerosol-generating device comprising:

-   -   a device cavity comprising a device cavity inner surface having         a device cavity inner diameter, the device cavity being         configured to receive at least the aerosol-forming substrate of         the aerosol-generating article; and     -   at least one heating element configured to heat the         aerosol-forming substrate when the aerosol-forming substrate is         received in the device cavity,

wherein, when the aerosol-forming substrate of the aerosol-generating article is received in the device cavity, an airflow passage is defined between the substrate outer surface and the device cavity inner surface, the airflow passage extending in the longitudinal direction along the length of the aerosol-forming substrate.

The aerosol-generating device comprises a device cavity. In use, an aerosol-forming substrate of an aerosol-generating article is received within the device cavity of the aerosol-generating device. The aerosol-generating article may then be heated by the heating element to release volatile compounds from the aerosol-forming substrate, which may condense to form an aerosol.

When the device cavity receives the aerosol-forming substrate, an airflow passage is defined by the substrate outer surface and the device cavity inner surface. The gap between the inner surface of the device cavity and outer surface of the substrate at least partially delimits the airflow passage. The airflow passage is external to the aerosol-forming substrate and is comprised within the device cavity of the aerosol-generating device.

The airflow passage may allow air drawn by a user to flow along an outer surface of the aerosol-forming substrate, rather than through the aerosol-forming substrate, thus reducing or minimising the amount of air that travels through the aerosol-forming substrate. As a result, airflow within the device primarily cools the outer surface of the substrate as it flows along the airflow passage, rather than cooling the substrate throughout its thickness. Advantageously, this may reduce fluctuations in the temperature of the substrate due to a user drawing on the aerosol-generating article.

Advantageously, providing an airflow passage between the substrate outer diameter and the device cavity inner diameter provides a space into which volatile compounds evolved from the heated aerosol-forming substrate may migrate. Such an airflow passage may promote the evolution of volatile compounds from the heated substrate, as air drawn through the article by a user is drawn over the outer surface of the substrate.

As used herein, the term “aerosol-generating device” refers to a device comprising a heating element that interacts with the aerosol-forming substrate of the aerosol-generating article to generate an aerosol.

According to another aspect of the invention, there is provided an aerosol-generating article suitable for the above aerosol-generating system, the article comprising:

an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end, the aerosol-generating article comprising:

an upstream segment disposed at the upstream end of the aerosol-generating article, the upstream segment comprising an aerosol-forming substrate, the substrate comprising a substrate outer surface having a substrate outer diameter; and

a downstream segment disposed at the downstream end of the aerosol-generating article, the downstream segment having a downstream segment outer diameter, the downstream segment outer diameter being greater than the substrate outer diameter.

The downstream segment has an outer diameter greater than the outer diameter of the aerosol-forming substrate. In comparison to aerosol-generating articles having a consistent outer diameter along the length of the article, providing an aerosol-generating article with segments having different outer diameters may enable a segment of the article comprising an aerosol-forming substrate to be thinner than other components of the article, such as a filter or cooling element. Advantageously, reducing the thickness of the aerosol-forming substrate may enable heat applied to the substrate from a heating element to propagate rapidly through the thickness of the substrate, reducing the time required for a heating element to raise the temperature of the substrate at the regions of the substrate that are furthest away from the heating element. This may reduce variations in temperature across the thickness of the aerosol-forming substrate, and reduce the likelihood of unheated and unused portions of aerosol-forming substrate remaining at regions of the substrate furthest away from the regions heated by a heating element. Since variations in the temperature across the thickness of the aerosol-forming substrate may be reduced, the composition and other properties of the aerosol generated from the substrate may be more uniform throughout a user experience, and may be easier to control between user experiences with different substrates. Advantageously, this may create a more consistent experience for a user.

Since the aerosol-generating article of this aspect of the invention is suitable for the aerosol-generating system of the previous aspect of the invention, the advantages specified above for the system also apply to the article itself.

The term “aerosol-generating article” is used herein to denote an article comprising an aerosol-forming substrate wherein the aerosol-forming substrate is heatable to produce and deliver an aerosol to a user. As used herein, the term “aerosol-generating substrate” denotes a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

The aerosol-generating article may generally take the form of a rod. The article may comprise a central longitudinal axis extending centrally through the rod in the longitudinal direction, from the upstream end to the downstream end. The upstream segment and the downstream segment of the aerosol-generating article may be arranged in coaxial alignment with the central longitudinal axis of the aerosol-forming article. The upstream segment and the downstream segment of the aerosol-generating article may be arranged end-to-end in coaxial alignment with the central longitudinal axis of the aerosol-forming article.

The aerosol-generating article may have a total length of between about 30 millimetres and about 100 millimetres.

In a preferred embodiment, the aerosol-generating article has a total length of between about 40 millimetres and about 50 millimetres. Preferably, the aerosol-generating article has a total length of about 45 millimetres.

The aerosol-generating article may comprise a plurality of components. For example, the aerosol-generating article may comprise an aerosol-forming substrate and any one or combination of any one or more of: a thermally conductive layer, a mouthpiece, a filter, a cooling element, a spacing element and a flavour element.

The downstream segment has a downstream segment outer diameter that is greater than the substrate outer diameter. The downstream segment outer diameter is greater than the substrate outer diameter at least at the upstream end of the downstream segment. As used herein, the term “upstream end” refers to the end of a feature or aspect of the article that is closest to the upstream end of the article, and the term “downstream end” refers to the end of a feature or aspect of the article that is closest to the downstream end of the article.

In some preferred embodiments, the downstream segment has a downstream segment outer diameter that is constant along the length of the downstream segment. However, in some embodiments the downstream segment outer diameter varies along the length of the downstream segment, from the upstream end to the downstream end of the article. The downstream segment outer diameter may increase from the upstream end of the downstream segment to the downstream end of the article. The downstream segment outer diameter may decrease from the upstream end of the downstream segment to the downstream end of the article.

The downstream segment may have a downstream segment outer diameter of between about 5 millimetres and about 13 millimetres. Preferably, the downstream segment has an outer diameter that is substantially constant along the length of the segment.

The downstream segment may have a length between about 7 millimetres and about 25 millimetres.

The downstream segment may comprise one or more components. For example, the downstream segment may comprise any one or any combination of any one or more of: a mouthpiece, a filter, a spacing element, a cooling element and a flavour element.

The upstream segment may comprise a mouthpiece. The mouthpiece is a component configured to be drawn on by a user to received aerosol from the aerosol-generating article when the aerosol-generating article is heated.

The upstream segment may comprise a filter. The term “filter” is used to indicate a section of the aerosol-generating article that is configured to remove at least partially gas phase or particulate phase constituents or both gas phase and particulate phase constituents from mainstream aerosol drawn through the filter. Therefore, the filter may be beneficial to minimise the presence of undesirable constituents in the formed aerosol. Preferably the filter is a cellulose acetate filter plug. Preferably, the downstream segment comprises mouthpiece in the form of a filter. Preferably, the downstream segment comprises a mouthpiece in the form of a filter that is about 7 millimetres in length, but can have a length of between about 5 millimetres to about 10 millimetres.

In some embodiments, the downstream segment consists of a filter. This may provide for a compact aerosol-generating article in which the number of parts is reduced to a minimum.

In some embodiments, at least one of a cooling element and a spacing element may be disposed between the aerosol-forming substrate and the filter. Such additional components may be used to improve the thermal or mechanical properties of the aerosol-generating article.

As used herein, a “cooling element” refers to a component of an aerosol-generating article located downstream of the aerosol-forming substrate such that, in use, an aerosol formed by volatile compounds released from the aerosol-forming substrate passes through and is cooled by the cooling element before being inhaled by the user. A cooling element has a large surface area, but causes a low pressure drop. Filters and other mouthpieces that produce a high pressure drop, for example filters formed from bundles of fibres, are not considered to be aerosol-cooling elements. Chambers and cavities within an aerosol-generating article are not considered to be aerosol cooling elements.

The spacing element may be a support element configured to resist downstream movement of the aerosol-forming substrate during insertion of a heating element into the aerosol-forming substrate. The spacing element may comprise a hollow tube. The spacing element may comprise a hollow tube of cellulose acetate.

In some embodiments, the downstream segment comprises a flavour element. The flavour element may comprise one or more flavourants. As used herein, the term “flavourant” denotes an agent that, in use, imparts one or both of a taste or aroma to an aerosol generated by heating the aerosol-forming substrate. An example of a suitable flavourant is menthol. The flavour element may be arranged at any suitable location in the downstream segment.

The upstream segment comprises the aerosol-forming substrate. The upstream segment may also comprise one or more additional components, such as a layer of thermally conductive material, a cooling element and a spacing element. Preferably the upstream segment consists of the aerosol-forming substrate and optionally a layer of thermally conductive material.

The upstream segment may have an outer diameter of between about 3 millimetres and about 12 millimetres. The upstream segment may have an outer diameter that is substantially constant along the length of the segment.

The upstream segment may have a length of between about 8 millimetres and 25 millimetres.

The aerosol-forming substrate has an aerosol-forming substrate outer surface having a substrate outer diameter. The aerosol-forming substrate may have an outer diameter of between about 3 millimetres and about 12 millimetres. Preferably, the substrate outer diameter is substantially constant along the length of the aerosol-forming substrate.

The substrate outer diameter may be between about 50% and about 98% of the downstream segment outer diameter, or between about 60% and about 95% of the downstream segment outer diameter, or between about 70% and about 90% of the downstream segment outer diameter.

The aerosol-forming substrate may have a length of between about 8 millimetres and about 12 millimetres.

The aerosol-forming substrate may have any suitable transverse cross-section. As used herein, a “transverse cross-section” is a cross section perpendicular to the longitudinal direction. For example, the substrate may have a circular, oval, stadium shaped, rectangular or triangular transverse cross-sectional shape. Preferably, the substrate has a circular transverse cross-sectional shape.

Preferably, the aerosol-forming substrate is a solid aerosol-forming substrate. Preferably, the aerosol-forming substrate comprises tobacco. Preferably the aerosol-forming substrate is a solid aerosol-forming substrate comprising tobacco. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating.

The solid aerosol-forming substrate may comprise a plug of tobacco. The plug of tobacco may comprise, for example, one or more of: powder, granules, pellets, shreds, strands, strips or sheets containing one or more of: herb leaf, tobacco leaf, tobacco ribs, expanded tobacco and homogenised tobacco. As used herein, the term ‘homogenised tobacco material’ denotes a material formed by agglomerating particulate tobacco. Providing homogenised tobacco material may improve aerosol generation, the nicotine content and the flavour profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenised tobacco involves grinding tobacco leaf, which more effectively enables the release of nicotine and flavours upon heating. Where the tobacco plug comprises homogenised tobacco material, the homogenised tobacco material may be in the form of a sheet. As used herein, the term ‘sheet’ denotes a laminar element having a width and length substantially greater than the thickness thereof.

The solid aerosol-forming substrate may comprise homogenised tobacco material. The solid aerosol-forming material may comprise shreds, strands or strips of homogenised tobacco material. The solid aerosol-forming substrate may comprise a sheet of homogenised tobacco material.

The aerosol-forming substrate may have a substantially homogenous composition. In an embodiment, the aerosol-forming substrate may have a substantially homogeneous composition in at least the longitudinal direction.

A sheet of homogenised tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems. A sheet of homogenised tobacco material may comprise one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed during, for example, the treating, handling and shipping of tobacco. A sheet of homogenised tobacco material are preferably formed by a casting process of the type generally comprising casting a slurry comprising particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form a sheet of homogenised tobacco material and removing the sheet of homogenised tobacco material from the support surface.

The solid aerosol-forming substrate may comprises a gathered sheet of homogenised tobacco material. As used herein, the term ‘gathered’ is used to describe a sheet that is convoluted, folded, or otherwise compressed or constricted substantially transversely to a longitudinal axis of the aerosol-generating article.

In some preferred embodiments, the aerosol-forming substrate comprises a gathered textured sheet of homogenised tobacco material. As used herein, the term ‘textured sheet’ denotes a sheet that has been crimped, embossed, debossed, perforated or otherwise deformed. Use of a textured sheet of homogenised tobacco material may advantageously facilitate gathering of the sheet of homogenised tobacco material to form the aerosol-forming substrate. The aerosol-forming substrate may comprise a gathered textured sheet of homogenised tobacco material comprising a plurality of spaced-apart indentations, protrusions, perforations or a combination thereof.

In a particularly preferred embodiment, the aerosol-forming substrate comprises a gathered crimped sheet of homogenised tobacco material. As used herein, the term ‘crimped sheet’ denotes a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend along or parallel to a longitudinal axis of the aerosol-generating article. This advantageously facilitates gathering of the crimped sheet of homogenised tobacco material to form the aerosol-generating article. However, it will be appreciated that crimped sheets of homogenised tobacco material for inclusion in the aerosol-generating article may alternatively or in addition have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article.

The aerosol-forming substrate may comprise tobacco-containing material and non-tobacco containing material.

The aerosol-forming substrate may comprise an aerosol former. The aerosol-forming substrate may comprise a single aerosol former or a combination of two or more aerosol formers. As used herein, the term ‘aerosol former’ is used to describe any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article. Suitable aerosol-formers include, but are not limited to: polyhydric alcohols, such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1,3-butanediol and, most preferred, glycerine. The aerosol-forming substrate may have an aerosol former content of greater than 5 percent on a dry weight basis. The aerosol aerosol-forming substrate may have an aerosol former content of between about 5 percent and about 30 percent on a dry weight basis. The aerosol-forming substrate may have an aerosol former content of about 20 percent on a dry weight basis.

The aerosol-forming substrate preferably comprises homogenised tobacco material, an aerosol-former and water.

The homogenised tobacco material may be provided in sheets which are one of folded, crimped, or cut into strips. In a particularly preferred embodiment, the sheets are cut into strips having a width of between about 0.2 millimetres and about 2 millimetres, more preferably between about 0.4 millimetres and about 1.2 millimetres. In one embodiment, the width of the strips is about 0.9 millimetres.

In some embodiments, the aerosol-forming substrate may comprise an inner cavity. In other words, the aerosol-forming substrate may be a hollow tubular substrate. The aerosol-forming substrate may comprise a substrate inner surface having a substrate inner diameter, the substrate inner surface delimiting an inner cavity extending in the longitudinal direction within the aerosol-forming substrate. Providing an inner cavity into the aerosol-forming substrate may enable a heating element to be inserted into the aerosol-forming substrate, in the cavity, without piercing the substrate and altering the structure of the substrate. The provision of an inner cavity may also be beneficial to further reduce the thickness of the aerosol-forming substrate, enhancing the heat transfer advantages explained above.

The substrate inner diameter may be between about 60% and about 90% of the substrate outer diameter, or may be between about 70% and about 90% or between about 80% and about 90%. Such ranges may provide the required propagation of heat within the aerosol-forming substrate while endowing the substrate with the required mechanical properties.

When the aerosol-forming substrate comprises a substrate inner surface delimiting an inner cavity, the substrate inner surface may have the same transverse cross-sectional shape as the substrate outer surface. In particular, the substrate inner surface may have a substantially circular, oval or stadium shaped transverse cross-section.

In some embodiments, the aerosol-generating article comprises a layer of thermally conductive material. In some embodiments, the layer of thermally conductive material may cover at least part of at least an otherwise exposed aerosol-forming substrate. In some embodiments, the layer of thermally conductive material may be disposed on at least the substrate outer surface. In some embodiments, the layer of thermally conductive material may be disposed on at least the substrate inner surface. In some embodiments, the layer of thermally conductive material may be disposed on at least the substrate inner surface and on the substrate outer surface. Providing a layer of thermally conductive material on an otherwise exposed substrate surface may enable heat from a heating element received by or engaged with the substrate to be distributed over a broader area of the aerosol-forming substrate, improving heat transfer efficiency between a heating element and the aerosol-forming substrate. The layer of thermally conductive material may also create a physical separation between a heating element received in the inner cavity and the aerosol-forming substrate, which may reduce the risk of overheating the aerosol-forming substrate in regions of the substrate close to the heating element. The layer of thermally conductive material may also increase the robustness of the tubular aerosol-forming substrate, which may have been reduced by the reduction in the thickness of the substrate by the provision of the inner cavity.

As used herein, “thermally conductive” refers to a material having a thermal conductivity of at least 10 W/m.k, preferably at least 40 W/m.k, more preferably at least 100 W/m.k at 23 degrees Celsius and a relative humidity of 50%. In preferred embodiments, the layer of thermally conductive material comprises material having a thermal conductivity of at least 40 W/m.k, preferably at least 100 W/m.k, more preferably at least 150 W/m.k, and even more preferably at least 200 W/m.k at 23 degrees Celsius and a relative humidity of 50%.

Examples of suitable conductive materials include, but are not limited to, aluminium, copper, zinc, nickel, silver, and combinations thereof.

The aerosol-forming substrate may be provided in a plurality of discrete segments. In some embodiments, each segment may comprise the same aerosol-forming substrate composition. In some embodiments, one or more segments may comprise aerosol-forming substrates having a different composition. The aerosol-forming substrate may comprise a first aerosol-forming substrate segment having a first composition, and a second aerosol-forming substrate segment having a second composition.

The different compositions of the first and second aerosol-forming substrate segments may enable aerosols having different compositions to be generated from a single aerosol-generating article. This may also enable a user to select a particular aerosol-forming substrate to be heated to generate a particular aerosol during an experience.

The first and second aerosol-forming substrate segments may be configured to be heated sequentially. This may be beneficial to establish a pre-determined user experience in which at least two types of aerosol are sequentially generated at a pre-set time.

In some preferred embodiments, the discrete segments may be arranged end-to-end in the longitudinal direction of the article.

In some embodiments, the aerosol-generating article may comprise a wrapper circumscribing the upstream segment. Advantageously, such a wrapper may prevent a user from handling the aerosol-forming substrate, which help to maintain a high level of hygiene. The wrapper may be made from any suitable material. In particular, the wrapper may be formed from a porous material. The wrapper may be made from a material that permits volatile compounds to be released from the aerosol-forming substrate when the wrapper is disposed around the downstream segment.

In some embodiments, the aerosol-generating article may comprise a wrapper circumscribing the downstream segment. Advantageously, where the downstream segment comprises a plurality of components, a wrapper may hold together the plurality of components.

In some embodiments, the aerosol-generating article may comprise a wrapper circumscribing the upstream segment and the downstream segment. Advantageously, the wrapper may hold the upstream segment and the downstream segment together.

Advantageously, the provision of one or more wrappers may improve the structural integrity of the aerosol-generating article.

The upstream segment and the downstream segment may be secured together. The upstream segment and the downstream segment may be secured together by any suitable means. For example, the aerosol-generating article may comprise a connection mechanism. The connection mechanism may contribute to holding the upstream segment and the downstream segment together. In an embodiment, the connection mechanism may comprise a cavity provided in the upstream end of the downstream segment in which the downstream end of the upstream segment is inserted. The downstream end of the upstream segment may comprise a protrusion inserted in the cavity.

When a wrapper circumscribing the downstream segment is provided and the aerosol-generating article comprises a connection mechanism, the wrapper may be configured to exert pressure on the connection mechanism. In an embodiment, the wrapper may exert pressure around the cavity receiving the downstream end of the downstream segment. This may additionally contribute to holding the upstream segment and the downstream segment together

The downstream segment outer diameter of the aerosol-generating article may be substantially the same as or greater than the device cavity inner diameter. This may be beneficial to ensure that the aerosol that exits the airflow passage through a downstream edge of the airflow passage may be drawn through the downstream segment instead of being directly released towards the outside of the aerosol-generating system.

The at least one heating element is positioned within the device cavity. The at least one heating element may be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements. For example, in some embodiments, the device comprises two or more heating elements. In some embodiments, the at least one heating element is arranged to heat the outer surface of the aerosol-forming substrate. In some preferred embodiments, the at least one heating element is arranged for at least partial insertion into an aerosol-forming substrate when the aerosol-forming substrate is received within the device cavity. Where the aerosol-forming substrate comprises an inner cavity, in some embodiments, the at least one heating element may be arranged for insertion into the inner cavity of the substrate when the aerosol-forming substrate is received in the device cavity. The at least one heating element may be an elongate heating element. The at least one elongate heating element may be blade-shaped. The at least one elongate heating element may be pin-shaped. The at least one elongate heating element may have a tapered shape, or at least a tapered end. The at least one elongate heating element may have a pointed end. The at least one elongate heating element may be cone-shaped. The at least one elongate heating element may be have any suitable shape arranged to facilitate insertion of the heating element into the aerosol-forming substrate. Advantageously, an elongate heating element may provide easier engagement or easier disengagement or both easier engagement and easier disengagement of the aerosol-forming substrate with the heating element of the device.

The at least one heating element may comprise at least one resistive heating element. Preferably, the at least one heating element comprises a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of a desired electrical power to the at least one heating element while reducing or minimising the voltage required to provide the desired electrical power. Advantageously, reducing or minimising the voltage required to operate the at least one heating element may facilitate reducing or minimising the physical size of the power supply.

In some embodiments, the at least one heating element may comprise an electrically insulating substrate, and one or more electrically conductive tracks on the electrically insulating substrate.

Preferably, the electrically insulating substrate is stable at an operating temperature of the at least one heating element. Preferably, the electrically insulating substrate is stable at temperatures of up to about 400 degrees Celsius, more preferably about 500 degrees Celsius, more preferably about 600 degrees Celsius, more preferably about 700 degrees Celsius, more preferably about 800 degrees Celsius. The operating temperature of the at least one heating element during use may be at least about 200 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 700 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 600 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 500 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 400 degrees Celsius.

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of: paper, glass, ceramic, anodized metal, coated metal, and Polyimide. The ceramic may comprise mica, Alumina (Al₂O₃) or Zircona (ZrO₂). Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 Watts per metre Kelvin, preferably less than or equal to about 20 Watts per metre Kelvin and ideally less than or equal to about 2 Watts per metre Kelvin.

Suitable materials for forming the at least one resistive heating element, and in particular the one or more electrically conductive tracks, include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetal® and iron-manganese-aluminium based alloys.

In some embodiments, the at least one resistive heating element comprises one or more stamped portions of electrically resistive material, such as stainless steel. Alternatively, the at least one resistive heating element may comprise a heating wire or filament, for example a Ni—Cr (Nickel-Chromium), platinum, tungsten or alloy wire.

In some embodiments, the at least one heating element may comprise an inductive heating element. The inductive heating element may comprise an inductor coil and a power supply configured to provide high frequency oscillating current to the inductor coil. As used herein, a high frequency oscillating current means an oscillating current having a frequency of between 500 kHz and 30 MHz. The at least one heating element may advantageously comprise a DC/AC inverter for converting a DC current supplied by a DC power supply to the alternating current. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field on receiving a high frequency oscillating current from the power supply. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field in the device cavity. In some preferred embodiments, the inductor coil may substantially circumscribe the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

The inductive heating element may comprise a susceptor element. As used herein, the term ‘susceptor element’ refers to an element comprising a material that is capable of converting electromagnetic energy into heat. Thus, when a susceptor element is located in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of hysteresis losses and/or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. Hysteresis losses occur in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains within the material being switched under the influence of an alternating electromagnetic field. Eddy currents may be induced if the susceptor material is electrically conductive. In case of an electrically conductive ferromagnetic or ferrimagnetic susceptor material, heat can be generated due to both eddy currents and hysteresis losses. Accordingly, the susceptor element may be heatable due to at least one of hysteresis losses or eddy currents, depending on the electrical and magnetic properties of the susceptor material.

The susceptor element is arranged such that, when the aerosol-generating article is received in the device cavity, the oscillating electromagnetic field generated by the inductor coil may induce a current in the susceptor element, causing the susceptor element to heat up. The aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m. The electrically-operated aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of between 1 and 30 MHz, for example between 1 and 10 MHz, for example between 5 and 7 MHz.

In some embodiments, a susceptor element is located in the aerosol-generating article. In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. The susceptor element may be located in the aerosol-forming substrate. Preferably, the susceptor element is an elongate susceptor that extends along the length of the substrate, in the longitudinal direction of the article. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be arranged in the inner cavity. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be arranged on the substrate inner surface. The aerosol-generating article may comprise one or more susceptor elements. The aerosol-generating article may comprise a plurality of susceptor elements.

In some embodiments, a susceptor element is located in the aerosol-generating device. In these embodiments, the susceptor element may be located in the device cavity. The susceptor element may be configured to be at least partially inserted into the aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received in the device cavity. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be configured to be at least partially inserted into the inner cavity of the aerosol-forming substrate when the aerosol-generating article is received in the device cavity. The susceptor element may extend into the device cavity in the longitudinal direction of the device cavity. The susceptor element may be elongate. The elongate susceptor element may be blade-shaped. The elongate susceptor element may be pin-shaped. The elongate susceptor element may have a tapered shape, or at least a tapered end. The elongate susceptor element may have a pointed end. The elongate susceptor element may be cone-shaped. The aerosol-generating device may comprise one or more susceptor elements. The aerosol-generating device may comprise a plurality of susceptor elements.

The susceptor element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for the elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel containing compounds, titanium, and composites of metallic materials. Preferred susceptor elements comprise a metal or carbon. Advantageously the susceptor element may comprise or consist of a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor element may be, or comprise, aluminium. The susceptor element preferably comprises more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials. Preferred elongate susceptor elements may be heated to a temperature in excess of 250 degrees Celsius.

The susceptor element may comprise a non-metallic core with a metal layer disposed on the non-metallic core. For example, the susceptor element may comprise metallic tracks formed on an outer surface of a ceramic core or substrate.

In some embodiments the aerosol-generating system comprises at least one resistive heating element and at least one inductive heating element. In some embodiments the aerosol-generating system comprises a combination of resistive heating elements and inductive heating elements.

The aerosol-generating device may comprise a plurality of heating elements. The aerosol-generating device may comprise a first heating element and a second heating element. In some embodiments, the second heating element may be spaced from the first heating element. The second heating element may be spaced from the first heating element in the longitudinal direction of the device cavity. The provision of heating elements spaced from one another may allow the aerosol-generating device to individually heat different sections of the aerosol-forming substrate when the aerosol-forming substrate is received in the device cavity.

The aerosol-forming substrate may comprise a first aerosol-forming substrate segment and a second aerosol-forming substrate segment. The first aerosol-forming substrate segment may be adjacent the second aerosol-forming substrate segment in the longitudinal direction. The first heating element may be arranged to heat the first longitudinal substrate segment and the second heating element may be arranged to heat the second longitudinal substrate segment when the aerosol-forming substrate is received in the device cavity.

The second aerosol-forming substrate segment may have a different composition to the first aerosol-forming substrate segment. The different compositions of the first and second aerosol-forming substrate segments may enable aerosols having different compositions to be generated from a single aerosol-generating article. This may enable the user to select a particular aerosol-forming substrate to be heated to generate a particular aerosol during an experience.

The first and second heating elements may be configured to heat the first and second aerosol-forming substrate segments sequentially during a user experience. This may be beneficial to establish a pre-determined user experience in which at least two types of aerosol are sequentially generated at a pre-set time.

The first heating element may be arranged to heat the first aerosol-forming substrate segment to a temperature at which volatile compounds are released from the first aerosol-forming substrate segment without heating the second aerosol-forming substrate segment to a temperature at which volatile compounds are released from the second aerosol-forming substrate segment. The second heating element may be arranged to heat the second aerosol-forming substrate segment to a temperature at which volatile compounds are released from the second aerosol-forming substrate segment without heating the first aerosol-forming substrate segment to a temperature at which volatile compounds are released from the first aerosol-forming substrate segment. In other words, each heating element may be arranged to heat an individual aerosol-forming substrate segment. This may facilitate sequential heating of such aerosol-forming substrate segments.

Preferably, the aerosol-generating device comprises a power supply. The power supply may be a DC voltage source. In preferred embodiments, the power supply is a battery. For example, the power supply may be a nickel-metal hydride battery, a nickel cadmium battery, or a lithium based battery, for example a lithium-cobalt, a lithium-iron-phosphate or a lithium-polymer battery. The power supply may alternatively be another form of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that allows for the storage of enough energy for use of the aerosol-generating device with one or more aerosol-forming substrates.

The power supply may be electrically connected to the at least one heating element for supplying power to the at least one heating element. When the heating element receives electrical power from the power supply, the heating element may generate heat. The power supply may be configured to supply sufficient power to the at least one heating element to heat the aerosol-forming substrate to a temperature at which volatile compounds are released from the substrate.

Preferably, the aerosol-generating device comprises a housing. Preferably, the housing at least partially defines the cavity for receiving an aerosol-forming substrate.

Preferably, the aerosol-generating device comprises at least one air inlet in fluid communication with the cavity. In embodiments in which the aerosol-generating device comprises a housing, preferably the housing at least partially defines the at least one air inlet. Preferably, the at least one air inlet is in fluid communication with an upstream end of the cavity. In embodiments in which the at least one heating element is an elongate at least one heating element positioned within the cavity, preferably the elongate at least one heating element extends into the cavity from the upstream end of the cavity.

The aerosol-generating device may comprises a controller. The controller may be configured to control the supply of power from the power supply to the at least one heating element. The controller may be any suitable controller. The controller may comprise any suitable electrical circuitry and electrical components. Preferably, the controller comprises a processor and a memory. The controller may comprise a microprocessor, which may be a programmable microprocessor.

The aerosol-generating device may comprise a sensor to detect air flow indicative of a user taking a puff. The air flow sensor may be an electro-mechanical device. The air flow sensor may be any of: a mechanical device, an optical device, an opto-mechanical device and a micro electro-mechanical systems (MEMS) based sensor. The aerosol-generating device may comprise a manually operable switch for a user to initiate a puff.

Preferably, the aerosol-generating device comprises an indicator for indicating when the at least one heating element is activated. The indicator may comprise a light, activated when the at least one heating element is activated.

The aerosol-generating device may comprise at least one of an external plug or socket and at least one external electrical contact allowing the aerosol-generating device to be connected to another electrical device. For example, the aerosol-generating device may comprise a USB plug or a USB socket to allow connection of the aerosol-generating device to another USB enabled device. For example, the USB plug or socket may allow connection of the aerosol-generating device to a USB charging device to charge a rechargeable power supply within the aerosol-generating device. The USB plug or socket may additionally, or alternatively, support the transfer of data to or from, or both to and from, the aerosol-generating device. Additionally, or alternatively, the aerosol-generating device may be connected to a computer to transfer data to the device, such as new heating profiles for new aerosol-generating articles.

In those embodiments in which the aerosol-generating device comprises a USB plug or socket, the aerosol-generating device may further comprise a removable cover that covers the USB plug or socket when not in use. In embodiments in which the USB plug or socket is a USB plug, the USB plug may additionally or alternatively be selectively retractable within the device.

According to a further aspect of the present invention, there is provided an aerosol-generating device for receiving an aerosol-forming substrate, the aerosol-generating device comprising:

at least one heating element;

a housing comprising a first housing part and a second housing part, the first housing part having a first cavity,

wherein the second housing part is moveable relative to the first housing part between an open position and a closed position;

wherein, in the closed position, the first cavity and the second housing part define a device cavity, the device cavity having an upstream end and a downstream end and defining a longitudinal direction between the upstream end and the downstream end,

wherein the at least one heating element is arranged to heat the aerosol-forming substrate when the aerosol-forming substrate is received in the device cavity; and

wherein, in the open position, an opening is formed between the first housing part and the second housing part to enable the aerosol-forming substrate to be inserted into the first cavity or removed from the first cavity in a direction different to the longitudinal direction.

Advantageously, the aerosol-generating device of this aspect enables aerosol-forming substrate to be inserted into a cavity of the device and removed from a cavity of a device in a direction other than a longitudinal direction of the cavity. This may enable the substrate to be inserted into the device cavity and removed from the device cavity particularly easily, reducing the risk of damaging the substrate or the device when inserting and removing aerosol-forming substrate.

In particular, the opening between the first housing part and the second housing part allows the aerosol-forming substrate to be inserted into the first cavity or removed from the first cavity in a direction different to the longitudinal direction. The direction different to the longitudinal direction may be any suitable direction that is different to the longitudinal direction. Preferably, the direction is substantially perpendicular to the longitudinal direction.

The device cavity may be an elongate cavity. In other words, the device cavity may have a length that is greater than the other dimensions of the cavity, such as the diameter. The length of the elongate device cavity may extend in the longitudinal direction. Typically the device cavity is a circularly cylindrical cavity. However, the device cavity may have any suitable shape and size. For example, the device cavity may have any suitable transverse cross-sections. In particular, the device cavity may have a circular, oval, stadium shaped, square or triangular transverse cross-section.

The device cavity may be configured to circumscribe the aerosol-forming substrate about the longitudinal direction. In other words, the device cavity may be configured to form a tube surrounding or enclosing the sides of the aerosol-forming substrate. The device cavity may have an open end. The device cavity may be open at both ends. The device cavity may have one open end and one substantially closed end. The open end may be at the downstream end of the device cavity and the substantially closed end may be at the upstream end of the device cavity. The substantially closed end may comprise one or more air inlets configured to enable ambient air to be drawn into the device cavity.

The device cavity may have one or more air inlets configured to enable ambient air to be drawn into the device cavity. The first housing portion may comprise one or more air inlets configured to enable ambient air to be drawn into the device cavity. The second housing portion may comprise one or more air inlets configured to enable ambient air to be drawn into the device cavity.

The aerosol-generating device of this aspect comprises at least one heating element. Preferably the device of this aspect comprises a plurality of heating elements. In some embodiments, at least one heating element is arranged in the first housing part. In some embodiments, at least one heating element is arranged in the second housing part.

The at least one heating element may be any suitable type of heating element. In some embodiments, the at least one heating element is arranged to heat the outer surface of the aerosol-forming substrate. In some preferred embodiments, the at least one heating element is arranged for at least partial insertion into an aerosol-forming substrate when the aerosol-forming substrate is received within the device cavity. Where the aerosol-forming substrate comprises an inner cavity, in some embodiments, the at least one heating element may be arranged for insertion into the inner cavity of the substrate when the aerosol-forming substrate is received in the device cavity. The at least one heating element may be an elongate heating element. The at least one elongate heating element may be blade-shaped. The at least one elongate heating element may be pin-shaped. The at least one elongate heating element may have a tapered shape, or at least a tapered end. The at least one elongate heating element may have a pointed end. The at least one elongate heating element may be cone-shaped. The at least one elongate heating element may be have any suitable shape arranged to facilitate insertion of the heating element into the aerosol-forming substrate. Advantageously, an elongate heating element may provide easier engagement or easier disengagement or both easier engagement and easier disengagement of the aerosol-forming substrate with the heating element of the device.

Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of a desired electrical power to the at least one heating element while reducing or minimising the voltage required to provide the desired electrical power. Advantageously, reducing or minimising the voltage required to operate the at least one heating element may facilitate reducing or minimising the physical size of the power supply.

In some embodiments, the at least one heating element may comprise an electrically insulating substrate, and one or more electrically conductive tracks on the electrically insulating substrate.

Preferably, the electrically insulating substrate is stable at an operating temperature of the at least one heating element. Preferably, the electrically insulating substrate is stable at temperatures of up to about 400 degrees Celsius, more preferably about 500 degrees Celsius, more preferably about 600 degrees Celsius, more preferably about 700 degrees Celsius, more preferably about 800 degrees Celsius. The operating temperature of the at least one heating element during use may be at least about 200 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 700 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 600 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 500 degrees Celsius. The operating temperature of the at least one heating element during use may be less than about 400 degrees Celsius.

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of: paper, glass, ceramic, anodized metal, coated metal, and Polyimide. The ceramic may comprise mica, Alumina (Al₂O₃) or Zircona (ZrO₂). Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 Watts per metre Kelvin, preferably less than or equal to about 20 Watts per metre Kelvin and ideally less than or equal to about 2 Watts per metre Kelvin.

Suitable materials for forming the at least one resistive heating element, and in particular the one or more electrically conductive tracks, include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetal® and iron-manganese-aluminium based alloys.

In some embodiments, the at least one resistive heating element comprises one or more stamped portions of electrically resistive material, such as stainless steel. Alternatively, the at least one resistive heating element may comprise a heating wire or filament, for example a Ni—Cr (Nickel-Chromium), platinum, tungsten or alloy wire.

In some embodiments, the at least one heating element may comprise an inductive heating element. The inductive heating element may comprise an inductor coil and a power supply configured to provide high frequency oscillating current to the inductor coil. As used herein, a high frequency oscillating current means an oscillating current having a frequency of between 500 kHz and 30 MHz. The at least one heating element may advantageously comprise a DC/AC inverter for converting a DC current supplied by a DC power supply to the alternating current. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field on receiving a high frequency oscillating current from the power supply. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field in the device cavity. In some preferred embodiments, the inductor coil may substantially circumscribe the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

The inductive heating element may comprise a susceptor element. As used herein, the term ‘susceptor element’ refers to an element comprising a material that is capable of converting electromagnetic energy into heat. Thus, when a susceptor element is located in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of hysteresis losses and/or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. Hysteresis losses occur in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains within the material being switched under the influence of an alternating electromagnetic field. Eddy currents may be induced if the susceptor material is electrically conductive. In case of an electrically conductive ferromagnetic or ferrimagnetic susceptor material, heat can be generated due to both eddy currents and hysteresis losses. Accordingly, the susceptor element may be heatable due to at least one of hysteresis losses or eddy currents, depending on the electrical and magnetic properties of the susceptor material.

The susceptor element is arranged such that, when the aerosol-generating article is received in the device cavity, the oscillating electromagnetic field generated by the inductor coil may induce a current in the susceptor element, causing the susceptor element to heat up. The aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m. The electrically-operated aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of between 1 and 30 MHz, for example between 1 and 10 MHz, for example between 5 and 7 MHz.

In some embodiments, a susceptor element is located in the aerosol-generating article. In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. The susceptor element may be located in the aerosol-forming substrate. Preferably, the susceptor element is an elongate susceptor that extends along the length of the substrate, in the longitudinal direction of the article. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be arranged in the inner cavity. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be arranged on the substrate inner surface. The aerosol-generating article may comprise one or more susceptor elements. The aerosol-generating article may comprise a plurality of susceptor elements.

In some embodiments, a susceptor element is located in the aerosol-generating device. In these embodiments, the susceptor element may be located in the device cavity. The susceptor element may be configured to be at least partially inserted into the aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received in the device cavity. Where the aerosol-forming substrate comprises an inner cavity, the susceptor element may be configured to be at least partially inserted into the inner cavity of the aerosol-forming substrate when the aerosol-generating article is received in the device cavity. The susceptor element may extend into the device cavity in the longitudinal direction of the device cavity. The susceptor element may be elongate. The elongate susceptor element may be blade-shaped. The elongate susceptor element may be pin-shaped. The elongate susceptor element may have a tapered shape, or at least a tapered end. The elongate susceptor element may have a pointed end. The elongate susceptor element may be cone-shaped. The aerosol-generating device may comprise one or more susceptor elements. The aerosol-generating device may comprise a plurality of susceptor elements.

The susceptor element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for the elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel containing compounds, titanium, and composites of metallic materials. Preferred susceptor elements comprise a metal or carbon. Advantageously the susceptor element may comprise or consist of a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor element may be, or comprise, aluminium. The susceptor element preferably comprises more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials. Preferred elongate susceptor elements may be heated to a temperature in excess of 250 degrees Celsius.

The susceptor element may comprise a non-metallic core with a metal layer disposed on the non-metallic core. For example, the susceptor element may comprise metallic tracks formed on an outer surface of a ceramic core or substrate.

In some embodiments the aerosol-generating system comprises at least one resistive heating element and at least one inductive heating element. In some embodiments the aerosol-generating system comprises a combination of resistive heating elements and inductive heating elements.

Preferably, the at least one heating element of this aspect is configured to be inserted into an aerosol-forming substrate when the first housing part and the second housing part are in the closed position and an aerosol-forming substrate is received in the device cavity. Accordingly, at least one heating element may protrude from the first housing portion into the device cavity when the first and second housing parts are in the closed position. Accordingly, at least one heating element may extend or protrude from the second housing portion into the device cavity when the first and second housing parts are in the closed position.

Where a heating element extends from one of the first and second housing portions into the device cavity, the heating element may extend into the device cavity in any suitable direction. In some embodiments, it is preferable that a heating element extends into the device cavity in a direction substantially perpendicular to the longitudinal direction. Where the device comprises a plurality of heating elements extending into the device cavity, it may be preferable that all of the heating elements are substantially parallel with each other.

The device of this aspect may comprise any suitable number of heating elements. For example, the device may comprise one, two, three, four, five, six, seven, eight, nine, ten, eleven or twelve heating elements. Where the device comprises a plurality of heating elements, the heating elements may be spaced apart. The heating elements may be spaced apart in a longitudinal direction of the device cavity, between an upstream end and a downstream end of the device cavity. The heating elements may be spaced apart in a transverse direction of the device cavity, parallel to the longitudinal direction.

In some embodiments, the device of this aspect comprises at least two heating elements, a first heating element and a second heating element, the second heating element being spaced apart from the first heating element in a longitudinal direction of the device cavity. In these embodiments, the device may be suitable for use with an aerosol-generating article comprising two or more segments of aerosol-forming substrate, spaced apart in a longitudinal direction, as described above in relation to a previous aspect. In these embodiments, the first heating element may be arranged to heat a first segment of aerosol-forming substrate received in the device cavity and a second heating element may be arranged to heat a second segment of aerosol-forming substrate received in the device cavity. The device may be configured to heat the first and second heating elements at different times, or to different temperatures to vary the aerosol generated by the system, and the experience of a user.

In some embodiments of the device of this aspect, the device comprises at least one heating element extending from the first housing portion and at least one heating element extending from the second housing portion. Advantageously, providing heating elements on both the first and second housing portions enables heating elements to be inserted into the aerosol-forming substrate from different sides, which may reduce variations in the temperature of the aerosol-forming substrate. Furthermore, the movement of the first and second housing portions between the open and closed positions enables the aerosol-forming substrate to be inserted into such a device, and removed from such a device, with ease.

The second housing part is movable relative to the first housing part. The first housing part and the second housing part may be movably couplable. The first and second housing parts may be movably coupled together by any suitable coupling means.

In some embodiments, the first and second housing parts may be slidably coupled together. In these embodiments, the first and second housing parts may be provided with complementary rails that enable the second housing part to slide relative to the first housing part between the open position and the closed position.

In some embodiments, the second housing part may be removably couplable to the first housing part. In these embodiments, the first and second housing parts may be in the open position when the second housing part is removed from the first housing part. In these embodiments, the first and second housing parts may be in the closed position when the second housing part is removably coupled to the first housing part.

In some preferred embodiments, the first and second housing parts are rotatably coupled together. The second housing part may be rotatably coupled to the first housing part and rotatable between the open position and the closed position. The first and second housing parts may be rotatably coupled by any suitable means. For example, the first and second housing parts may be rotatably coupled by a pivot or a hinge.

The second housing part may be rotatable relative to the first housing part in any suitable direction. Preferably, the second housing part is rotatable relative to the first housing part in a direction perpendicular to the longitudinal direction. This may facilitate insertion of aerosol-forming substrate into a cavity of the device and removal of aerosol-forming substrate from a cavity of the device when the first and second housing portions are in the open position in a different direction to the longitudinal direction.

In some preferred embodiments, the second housing part comprises a second cavity. The second cavity may be arranged such that, in the closed position, the first cavity and the second cavity define the device cavity. In other words, the first cavity and the second cavity may align to form a larger cavity, the device cavity, when the first housing part and the second housing part are in the closed position.

In some embodiments the second cavity is different to the first cavity. This may enable the first and second cavities to form a device cavity having an unsymmetrical shape.

Preferably, the second cavity is substantially identical to the first cavity, having the same shape and size. For example, the first cavity may be substantially hemi cylindrical and the second cavity may be substantially hemi cylindrical, the first and second cavities forming a substantially cylindrical device cavity when the first and second housing parts are in the closed position. The first and second cavities may have any suitable size and shape for accommodating any suitable amount of aerosol-forming substrate.

In all other aspects, the aerosol-generating devices of this aspect may be the same as the aerosol-generating devices described above in relation to earlier aspects.

For example, the device preferably comprises one or more air inlets configured to enable ambient air to be drawn into the device cavity, a power supply for supplying power to the at least one heating element, and a controller for controlling the supply of power from the power supply to the at least one heating element.

According to a further aspect of the present invention, there is provided an aerosol-generating system comprising:

the aerosol-generating device according to the previous aspect; and

an aerosol-generating article comprising an aerosol-forming substrate.

The aerosol-generating articles used in combination with the aerosol-generating device of this aspect may comprise the same features as the aerosol-generating articles described above in relation to earlier aspects of the invention. However, it will also be appreciated that other aerosol-generating articles may also be suitable to be used in this system with the devices of the previous aspect. For example, aerosol-generating articles having a substantially constant outer diameter along their length may be suitable for use with the device of the previous aspect.

These and other features and advantages of the invention will become more evident in the light of the following detailed description of preferred embodiments, given only by way of illustrative and non-limiting example, in reference to the attached figures:

FIG. 1 shows a schematic illustration of an aerosol-generating article according to a first embodiment of the invention.

FIG. 2 shows a schematic illustration of an aerosol-generating article according to a second embodiment of the invention.

FIG. 3 shows a schematic illustration of an aerosol-generating system according to a third embodiment of the invention, the aerosol-generating system comprising the aerosol-generating article of FIG. 1.

FIG. 4 shows a schematic illustration of an aerosol-generating system according to a fourth embodiment of the invention.

FIG. 5 shows a schematic illustration of an aerosol-generating system according to a fifth embodiment of the invention.

FIG. 6 shows a schematic illustration of an aerosol-generating system according to a sixth embodiment of the invention.

FIG. 7 shows a schematic illustration of an aerosol-generating device according to a seventh embodiment of the invention.

FIG. 8 shows a schematic illustration of an aerosol-generating system according to an eighth embodiment of the invention, comprising the aerosol-generating device of FIG. 7.

FIG. 1 shows an aerosol-generating article 10 comprising an upstream end 11 and a downstream end 12. The article 10 comprises an upstream segment, which comprises an aerosol-forming substrate 13, and a downstream segment 14, which in this embodiment consists of a filter 15. The filter 15 generally forms a cylindrical part of cellulose acetate, having an outer cylindrical surface with a downstream segment outer diameter D1. In this embodiment, the aerosol-forming substrate 13 generally forms a hollow, cylindrical tube of homogenised cast leaf tobacco. The tubular aerosol-forming substrate 13 has a substrate outer surface 17 having a substrate outer diameter D2 and a substrate inner surface 18 having a substrate inner diameter D3. The substrate inner surface 18 delimits an inner cavity 16 extending in the longitudinal direction within the aerosol-forming substrate 13.

The outer diameter D1 of the filter is greater than the outer diameter D2 of the substrate.

The thickness of the aerosol-forming substrate 13 is significantly reduced compared to the thickness of aerosol-forming substrates in articles having a consistent outer diameter along their length and articles in which the aerosol-forming substrate is not tubular. The reduced thickness of the aerosol-forming substrate 13 may enable heat applied to the substrate 13 to propagate rapidly through the thickness of the substrate. This may reduce the time required to raise the temperature of substrate 13. For example, this may reduce the time required to raise the temperature of the substrate 13 at regions of the substrate 13 that are furthest away from a heating element 31. The reduced thickness of the aerosol-forming substrate 13 of the aerosol-generating article 10 may improve efficiency of aerosol generation from the aerosol-generating article.

The aerosol-generating article 10 of FIG. 2 is similar to the article of the embodiment of FIG. 1 except in that the downstream segment 14 comprises a spacing element 19 and a filter 15. In this embodiment, a spacing element 19 is disposed between the filter 15 and the aerosol-forming substrate 13.

In this embodiment, the spacing element 19 is a support element. However, it will be appreciated that in other embodiments the article may be provided with a cooling element disposed between the filter 15 and the substrate 13 in addition to or instead of the support element.

FIG. 3 shows an aerosol-generating system 40 comprising the aerosol-generating article 10 of FIG. 1 and an aerosol generating device 30. The aerosol-generating device 30 comprises a heating element 31 which is configured to be inserted into the aerosol-forming substrate 13 when the aerosol-generating article is received in the device 30. In the embodiment of FIG. 3, the heating element 31 is received in the inner cavity 16 of the article 10, defined by the substrate inner surface 18.

The aerosol-generating device 30 comprises a device cavity 32 having a device cavity inner surface 33. The device cavity inner surface 33 has a device cavity inner diameter D4. In FIG. 3, the device cavity 32 receives the aerosol-forming substrate 13 of the article 10. When the aerosol-forming substrate 13 is received in the device cavity 32, an annular gap is formed between the substrate outer surface 17 and the device cavity inner surface 33, which provides an airflow passage 35 in the longitudinal direction along the length of the substrate 13, and circumscribing the substrate. The width of the airflow passage 35 is the difference between the chamber inner diameter D4 and the substrate outer diameter D2. The airflow passage 35 is external to the aerosol-forming substrate 13.

When the aerosol-generating system 40 is in use, as depicted in FIG. 3, power is provided to the heating element 31 to heat the aerosol-forming substrate 13 to a temperature at which volatile compounds are released from the substrate 13. A user drawing on the downstream segment 14, such as on the filter 15, of the article 10 causes air to be drawn into the airflow passage 35 though air inlets 36 at a distal end of the device cavity 32, along the airflow passage 35 in the longitudinal direction of the article 10, and out of the device cavity 32 through the downstream segment 14, such as through the filter 15. Volatile compounds released from the heated aerosol-forming substrate 13 evolve into the airflow passage 35, as is schematically represented by curved arrows in FIG. 3, and cool to form an aerosol that can be inhaled by a user. The aerosol is entrained in the air being drawn through the airflow passage 35 and flows out of the device cavity 32 through the filter 15 of the article 10 towards the downstream end 12, as indicated by arrow A1.

In the embodiment of FIG. 3, the downstream segment outer diameter D1 is the same as the device cavity inner diameter D4. Therefore, the airflow passage is delimited at its downstream edge by the downstream segment 14, which in this embodiment corresponds to the filter 15. Accordingly, aerosol that exits the airflow passage 35 is required to flow through the filter 15.

In the aerosol-generating system 40 of FIG. 4, the aerosol-generating article 10 differs from that of FIGS. 1 and 3 in that the aerosol-forming substrate 13 does not comprise an inner cavity; instead, the aerosol-forming substrate 13 is a solid, cylindrical plug of homogenised tobacco cast leaf. The aerosol-generating device 30 is identical to that of FIG. 3, except in that it comprises a heating element 31 that penetrates the aerosol-forming substrate 13 when the aerosol-forming substrate 13 is received in the device cavity 32. In some embodiments, the heating element is any of: a blade, a pin, a spike or any other shape configured to facilitate insertion of the heating element into the aerosol-forming substrate. For example, the heating element may have a tapered or pointed end. In the embodiment of FIG. 4, the heating element is a blade-shaped heating element.

In the aerosol-generating system 40 of FIG. 5, the aerosol-generating article 10 differs from that of FIGS. 1 and 3 in that the aerosol-generating article 10 comprises a downstream segment 14, which in this embodiment is a filter 15, having a downstream segment outer diameter D1 which is greater than the device cavity inner diameter D4. Such a downstream segment configuration may further ensure that the upstream edge of the filter 15 delimits the downstream edge of the airflow passage 35. In addition, a layer of thermally conductive material 23 is disposed on the substrate inner surface 18. The layer of thermally conductive material 23 substantially covers the substrate inner surface 18, circumscribing the inner cavity 16 and extending the entire length of the inner cavity 16. This may improve the distribution of heat from the heating element 31 to the substrate 13. The layer of thermally conductive material 23 may also create a physical separation between a heating element 31 received in the inner cavity 16 and the aerosol-forming substrate 13, which may reduce the risk of overheating the aerosol-forming substrate 13 in regions of the substrate 13 close to the heating element 31. The layer of thermally conductive material 23 may also increase the robustness of the tubular aerosol-forming substrate 13, which may have been diminished by the reduction in the thickness of the substrate 13 by the provision of the inner cavity 16.

The other features of the system 40 of FIG. 5 correspond to those of the system 40 of FIG. 3.

In the aerosol-generating system 40 of FIG. 6, the aerosol-generating device 30 comprises a first heating element 34 and a second heating element 38 spaced apart from one another in the longitudinal direction of the device cavity 32. The aerosol-generating article 10 comprises an aerosol-forming substrate 13 having two aerosol-forming substrate segments, a first aerosol-forming substrate segment 21 and a second aerosol-forming segment 22, arranged end-to-end in the longitudinal direction of the article. The first aerosol-forming substrate segment 21 comprises a first aerosol-forming substrate composition, and the second aerosol-forming substrate segment 22 comprises a second aerosol-forming substrate composition, different from the composition of the first longitudinal substrate segment 21.

The first heating element 34 is arranged to heat the first aerosol-forming substrate segment 21 and the second heating element 38 is arranged to heat the second aerosol-forming substrate segment 22 when the aerosol-forming substrate 13 is received in the device cavity 32. Accordingly, the aerosol-generating device 30 can be configured to individually heat each segment of the aerosol-forming substrate 13. Since heat can be selectively applied to the first substrate segment 21 and the second substrate segment 22, the segments 21, 22 can be sequentially heated by the aerosol-generating device 40. Each segment can also be heated according to the type of aerosol the user wishes to consume.

The aerosol-generating device 30 of FIG. 6 further comprises a sensor 37 disposed within the device cavity 32, on the device cavity inner surface 33, and within the airflow passage 35 when the aerosol-forming substrate 13 is received in the device cavity 32. The sensor 37 may provide the device and/or the user with relevant data such as the start of a puff, the duration of a puff, the temperature of the aerosol or the concentration of a certain component of the aerosol within the airflow passage 35.

FIG. 7 shows an aerosol-generating device 300 according to a further embodiment of the invention. The device 300 comprises a housing that is capable of forming a device cavity 305 for receiving an aerosol-forming substrate. The housing comprises a first housing part 301 and a second housing part 302, which are movable relative to one another. In this embodiment, the first and second housing parts 301, 302 are rotatable relative to each other, and the relative movement is represented by arrow R1 in FIG. 7. A hinge 307 rotatably attaches the first housing part 301 to the second housing part 302.

The first and second housing parts 301, 302 are rotatable between an open position and a closed position. In the closed position, the first and second housing parts 301, 302 are arranged to form a device cavity for receiving an aerosol-forming substrate 130. In the closed position, the formed device cavity may circumscribe the aerosol-forming substrate. In the open position, the first and second housing parts 301, 302 are arranged to permit an aerosol-forming substrate 130 to be received on and removed from the bodies 301, 302.

The first housing part 301 comprises a first cavity 303 and the second housing part 302 comprises a second cavity 304. In this embodiment, the first cavity 303 is a substantially hemi cylindrical cavity, and the second cavity 304 is a substantially hemi cylindrical cavity. In the closed position, the first cavity 303 and the second cavity 304 are aligned to form the device cavity 305 for receiving the aerosol-forming substrate 130. In this embodiment, the device cavity 305 circumscribes the aerosol-forming substrate 130 about a longitudinal direction X when the aerosol-forming substrate 130 is received in the device cavity 305. In other words, the device cavity 305 forms a tubular cavity that surrounds or encloses the aerosol-forming substrate 130, the tubular cavity having a length extending in the longitudinal direction X. The tubular cavity maybe closed at an end. In the open position, the first cavity 303 and the second cavity 304 are rotated to form an opening 306, through which aerosol-forming substrate 130 may be inserted into each of the first and second cavities 303, 304 in a direction different from the longitudinal direction X, as shown in FIG. 7. In this embodiment, the aerosol-forming substrate 130 may be inserted into either of the first and second cavities 303, 304 in a direction substantially perpendicular P1 to the longitudinal direction X.

The aerosol-generating device 300 comprises a plurality of internal heating elements 310. The internal heating elements 310 are configured for at least partially penetrating the aerosol-forming substrate. In this embodiment, the internal heating elements 310 are pin-shaped heating elements 310. The first housing part 301 comprises a plurality of the pin-shaped heating elements 310 extending into the first cavity 303, and the second housing part 302 comprises a plurality of the pin-shaped heating elements 310 extending into the second cavity 304. Specifically, in the illustrated embodiment, the device 300 comprises twelve heating elements 310, six heating elements 310 extending from the first housing part 301 into the first cavity 303 and six heating elements 310 extending from the second housing part 302 into the second cavity 304. The pin shaped heating elements 310 extend in a substantially transverse direction within the chamber 305. The pin shaped heating 310 elements are arranged to extend substantially parallel to each other and perpendicular to the longitudinal direction X of the cavity, when the first and second housing parts 301, 302 are in the closed position. Although pin-shaped heating elements are described and illustrated herein, it will be appreciated that any of a variety of shapes may be used. For example, the heating elements may have the shape of any one or combination of: a blade, a pin, a spike or any other shape configured to facilitate insertion of the heating element into the aerosol-forming substrate. For example, the heating element may have a tapered or pointed end. The heating elements in the first cavity 303 may be the same as each another or may vary. The heating elements in the second cavity 304 may be the same as each other, or may vary. The heating elements in the first cavity 303 may have the same shape or may have different shapes compared to the heating elements in the second cavity 304. Although twelve heating elements are described with reference to the illustrated embodiment, it will be appreciated that other numbers of heating elements may be used. Although the illustrated invention describes heating elements in both cavities 303, 304, it will be appreciated that in some embodiments, there may only be heating elements extending from one cavity.

Each of the first and second housing parts 301, 302 further comprises air inlets 360. The air inlets 360 are arranged at one end of the device cavity 305, and are arranged to enable ambient air to be drawn into the device cavity 305.

FIG. 8 shows a longitudinal cross-section of the aerosol-generating device 300 of FIG. 7 in the closed position, in use with an aerosol-generating article 100. The aerosol-generating article 100 shown in FIG. 8 is similar to that of FIG. 1. The article 100 comprises an aerosol-forming substrate 130 in an upstream segment. The article 100 comprises a downstream segment 140 which, in this embodiment, comprises a filter 150 directly downstream of the aerosol-forming substrate 130. In the embodiment shown in FIG. 8, the aerosol-forming substrate 130 has a cylindrical tubular shape, having an inner cavity 160. However, it will be appreciated that other aerosol-generating articles, and particularly non-tubular aerosol-generating articles, may be equally suitable for use with the aerosol-generating device of FIG. 7.

The device cavity 30 of the aerosol-generating device 300 extends in a longitudinal direction X, from an upstream end 308 of the device cavity to a downstream end 309 of the device cavity. In the closed position, the first cavity 303 and the second cavity 304 align to form the substantially cylindrical device cavity 305.

When the aerosol-forming substrate 130 is disposed in the first cavity 303 and the first and second housing parts 301, 302 are in the open position, the pin-shaped heating elements 310 of the first housing part 301 pierce the aerosol-forming substrate. When the first housing part 301 and the second housing part 302 are moved to the closed position, the aerosol-forming substrate is held in the cylindrical device cavity 305 and the pin-shaped heating elements 310 of the second housing part 302 also pierce the aerosol-forming substrate 130. As shown in FIG. 8, the pin shaped heating elements 310 are spaced apart from each other both in the longitudinal direction X and in a transverse direction. In this way, the pin shaped heating elements 310 are arranged to heat different portions of the aerosol-forming substrate 130. Advantageously, this should ensure that all of the aerosol-forming substrate 130 is heated to the desired temperature during use of the system 400.

In use, when a user draws on the filter 150 of the aerosol-generating article 100, air is drawn into the device cavity through air inlets 360 at the upstream end 308 of the device cavity. In this embodiment, the air inlets 360 are directed towards a central longitudinal axis of the device chamber. The air drawn into the device cavity from the air inlets 360 enters the inner cavity 160 of the aerosol-forming substrate 130, is drawn along the inner cavity 160 towards the filter 150, as indicated by arrow A10, and is released from the filter 150 at a downstream end 120 of the aerosol-generating article 100 where it is delivered to the user.

When power is provided to the plurality of heating elements 310, the plurality of heating elements 310 heat the aerosol-forming substrate 130 to a temperature at which volatile compounds are released from the substrate 130, which are released from the substrate 130 into the inner cavity 160 of the substrate 130 and cool to form an aerosol that can be inhaled by a user. The aerosol is entrained in the air drawn through the inner cavity 160 and is drawn out of the inner cavity 160 through the filter 150 and delivered to the user at the downstream end 120. 

1.-14. (canceled)
 15. An aerosol-generating system, comprising: an aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end, the aerosol-generating article comprising: an upstream segment disposed at the upstream end of the aerosol-generating article, the upstream segment comprising an aerosol-forming substrate, the aerosol-forming substrate comprising a substrate outer surface having a substrate outer diameter, and a downstream segment disposed at the downstream end of the aerosol-generating article, the downstream segment having a downstream segment outer diameter, the downstream segment outer diameter being greater than the substrate outer diameter; and an aerosol-generating device comprising: a device cavity comprising a device cavity inner surface having a device cavity inner diameter, the device cavity being configured to receive at least the aerosol-forming substrate of the aerosol-generating article, and at least one heating element configured to heat the aerosol-forming substrate when the aerosol-forming substrate is received in the device cavity, wherein, when the aerosol-forming substrate of the aerosol-generating article is received in the device cavity, an airflow passage is defined between the substrate outer surface and the device cavity inner surface, the airflow passage extending in the longitudinal direction along a length of the aerosol-forming substrate.
 16. The aerosol-generating system of claim 15, wherein the aerosol-forming substrate further comprises a substrate inner surface having a substrate inner diameter, the substrate inner surface delimiting an inner cavity extending in the longitudinal direction within the aerosol-forming substrate.
 17. The aerosol-generating system of claim 16, wherein the substrate inner diameter is between about 60% and about 90% of the substrate outer diameter.
 18. The aerosol-generating system of claim 16, wherein a layer of thermally conductive material is disposed on the substrate inner surface.
 19. The aerosol-generating system of claim 15, wherein the upstream segment and the downstream segment are arranged in coaxial alignment with a longitudinal axis of the aerosol-generating article.
 20. The aerosol-generating system of claim 15, wherein the downstream segment comprises a filter.
 21. The aerosol-generating system of claim 20, wherein the downstream segment further comprises at least one of a cooling element and a spacing element disposed between the aerosol-forming substrate and the filter.
 22. The aerosol-generating system of claim 15, wherein the substrate outer diameter is between about 50% and about 98% of the downstream segment outer diameter.
 23. The aerosol-generating system of claim 15, wherein the substrate outer surface has a transverse cross-section with a circular shape or an oval shape.
 24. The aerosol-generating system of claim 15, wherein the aerosol-forming substrate further comprises tobacco cast leaf.
 25. The aerosol-generating system of claim 15, wherein the aerosol-forming substrate has a substantially homogenous composition in the longitudinal direction.
 26. The aerosol-generating system of claim 15, wherein the aerosol-forming substrate further comprises a first aerosol-forming substrate segment extending in the longitudinal direction, and a second aerosol-forming substrate segment adjacent the first aerosol-forming substrate segment in the longitudinal direction.
 27. The aerosol-generating system of claim 15, wherein the device cavity defines the longitudinal direction between an upstream end of the device cavity and a downstream end of the device cavity, and wherein the at least one heating element comprises a first heating element and a second heating element spaced from each other in the longitudinal direction of the device cavity.
 28. The aerosol-generating system of claim 15, wherein the downstream segment outer diameter of the aerosol-generating article is substantially the same as or greater than the device cavity inner diameter. 